Position estimation device and position estimation method

ABSTRACT

[Solution] Provided is a device including: an acquisition unit that acquires information indicating a position estimation system selected from among a plurality of position estimation systems for estimating a position of a flight vehicle; and a position estimation unit that estimates the position of the flight vehicle from first information generated by using an inertial sensor of the flight vehicle and second information generated through the position estimation system based on a parameter for the position estimation system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International PatentApplication No. PCT/JP2015/076315 filed on Sep. 16, 2015, which claimspriority benefit of Japanese Patent Application No. JP 2014-212311 filedin the Japan Patent Office on Oct. 17, 2014. Each of theabove-referenced applications is hereby incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present disclosure relates to a device, a method, and a program.

BACKGROUND ART

For passenger planes, functions including automatic flight have beenrealized by posture estimation, position estimation, and the like usinga combination of a highly precise inertial sensor and a GPS (GlobalPositioning System) receiver. In recent years, decreases in the size andthe cost of inertial sensors have advanced, and as a result, an inertialsensor and a GPS receiver have been mounted even on small flightvehicles to perform position estimation, posture estimation, and thelike.

For example, Patent Literature 1 discloses a technology of determining arest state of a moving body by using a combination of a GPS receiver andan inertial sensor.

CITATION LIST Patent Literature

Patent Literature 1: JP 2008-232869A

DISCLOSURE OF INVENTION Technical Problem

However, such small flight vehicles may fly in locations where it isdifficult to perform position estimation by using the GPS receiverunlike passenger planes. Since the inertial sensor in small flightvehicles generally exhibits low precision, the position of each flightvehicle is not appropriately estimated if it becomes difficult toperform position estimation by using the GPS receiver. As a result, itmay not be possible to cause the flight vehicles to fly as desired.

Thus, it is desirable to provide a mechanism that makes it possible tomore favorably estimate the position of a flight vehicle.

Solution to Problem

According to the present disclosure, there is provided a deviceincluding: an acquisition unit that acquires information indicating aposition estimation system selected from among a plurality of positionestimation systems for estimating a position of a flight vehicle; and aposition estimation unit that estimates the position of the flightvehicle from first information generated by using an inertial sensor ofthe flight vehicle and second information generated through the positionestimation system based on a parameter for the position estimationsystem.

In addition, according to the present disclosure, there is provided amethod including causing a processor to acquire information thatindicates a position estimation system selected from among a pluralityof position estimation systems for estimating a position of a flightvehicle, and estimate the position of the flight vehicle from firstinformation generated by using an inertial sensor of the flight vehicleand second information generated through the position estimation systembased on a parameter for the position estimation system.

In addition, according to the present disclosure, there is provided aprogram that causes a processor to acquire information that indicates aposition estimation system selected from among a plurality of positionestimation systems for estimating a position of a flight vehicle, andestimate the position of the flight vehicle from first informationgenerated by using an inertial sensor of the flight vehicle and secondinformation generated through the position estimation system based on aparameter for the position estimation system.

Advantageous Effects of Invention

As described above, the present disclosure makes it possible to morefavorably estimate the position of a flight vehicle. Note that theeffects described above are not necessarily limitative. With or in theplace of the above effects, there may be achieved any one of the effectsdescribed in this specification or other effects that may be graspedfrom this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for explaining a first example ofposture estimation using a combination of a gyro sensor and anacceleration sensor.

FIG. 2 is an explanatory diagram for explaining a second example ofposture estimation using a combination of a gyro sensor and anacceleration sensor.

FIG. 3 is an explanatory diagram for explaining an example of positionestimation using a combination of an inertial sensor and another sensor.

FIG. 4 is an explanatory diagram illustrating an example of an outlineconfiguration of a system according to an embodiment of the presentdisclosure.

FIG. 5 is a block diagram illustrating a configuration of a flightvehicle according to the embodiment.

FIG. 6 is an explanatory diagram for explaining a first example ofimaging by a monocular imaging device installed on the flight vehicle byusing a gimbal.

FIG. 7 is an explanatory diagram for explaining a second example ofimaging by a monocular imaging device installed on the flight vehicle byusing a gimbal.

FIG. 8 is an explanatory diagram for explaining an example of markerarrangement.

FIG. 9 is an explanatory diagram for explaining an example of a casewhere motion capturing is used.

FIG. 10 is an explanatory diagram for explaining features of eachposition estimation system.

FIG. 11 is an explanatory diagram for explaining an example of positionestimation based on a time delay parameter.

FIG. 12 is an explanatory diagram for explaining an example of a resultof position estimation without using the time delay parameter.

FIG. 13 is an explanatory diagram for explaining an example of a resultof position estimation based on the time delay parameter.

FIG. 14 is an explanatory diagram for explaining a first example ofselecting (switching) the position estimation system.

FIG. 15 is an explanatory diagram for explaining a second example ofselecting (switching) the position estimation system.

FIG. 16 is an explanatory diagram for explaining the second example ofselecting (switching) the position estimation system.

FIG. 17 is a flowchart illustrating an example of an outline flow ofposition estimation processing according to the embodiment.

FIG. 18 is a flowchart illustrating an example of an outline flow offirst selection processing according to the embodiment.

FIG. 19 is a flowchart illustrating an example of an outline flow ofsecond selection processing according to the embodiment.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

In the specification and the drawings, different letters will be addedafter the same reference numerals for discriminating between elementswith substantially the same functional configurations in some cases. Forexample, a plurality of elements with substantially the same functionalconfigurations will be discriminated between motors 120A, 120B, and 120Cas needed. However, if it is not particularly necessary to discriminatebetween each of a plurality of elements with substantially the samefunctional configurations, only a common reference numeral will beadded. For example, the motors 120A, 120B, and 120C will simply bereferred to as a motor 120 if it is not particularly necessary todiscriminate between the motors 120A, 120B, and 120C.

The following description will be given in the following order.

1. Basic posture estimation and position estimation

2. Outline configuration of system

3. Configuration of flight vehicle

4. Position estimation according to embodiment

5. Flow of processing

6. Conclusion

1. BASIC POSTURE ESTIMATION AND POSITION ESTIMATION

First, an example of basic posture estimation and position estimationwill be described with reference to FIGS. 1 to 3.

(1) Inertial Sensor

For example, an inertial sensor of a flight vehicle can include a gyrosensor (or an angular velocity sensor) that detects an angular velocityof the flight vehicle and an acceleration sensor that measuresacceleration of the flight vehicle. The inertial sensor can furtherinclude a digital compass (or a geomagnetic sensor).

(2) Posture Estimation

(a) Estimation from Angular Velocity

For example, a variation in the posture of the flight vehicle iscalculated by integrating the angular velocity that is detected by thegyro sensor. Therefore, the posture of the flight vehicle is calculatedfrom an initial value of the posture of the flight vehicle and thevariation in the posture of the flight vehicle.

The angular velocity that is detected by the gyro sensor has a driftproperty of a slow variation over time while exhibiting high reliabilityin a short period of time. Therefore, errors in the posture areaccumulated over time in a case of calculating the posture only from theangular velocity (and the initial value) detected by the gyro sensor.

(b) Estimation from Acceleration

On the assumption that the flight vehicle has hovered and has not moved,for example, the posture of the flight vehicle can be calculated from agravity direction detected by the acceleration sensor.

The acceleration detected by the acceleration sensor includeshigh-frequency noise due to influences of vibration and the like.However, since the gravity direction is always the same regardless oftime, the acceleration sensor has high reliability over a long period oftime.

(c) Sensor Fusion

Configuring a complementary filter by using the properties of the gyrosensor and the properties of the acceleration sensor as described abovemakes it possible to calculate the posture with high reliability. Such acombination of a plurality of sensors can be referred to as sensorfusion. Hereinafter, a condition example will be described withreference to FIGS. 1 and 2.

FIG. 1 is an explanatory diagram for illustrating a first example ofposture estimation using a combination of the gyro sensor and theacceleration sensor. Referring to FIG. 1, posture y₁(t) is calculatedfrom the acceleration that is detected by the acceleration sensor, andposture y₂(t) is calculated from the angular velocity that is detectedby the gyro sensor. y₁(t) is represented by x(t)+n₁(t), and y₂(t) isrepresented by x(t)+n₂(t). x(t) is an actual posture of the flightvehicle, n₁(t) is high-frequency noise due to the acceleration sensor,and n₂(t) is low-frequency noise due to the gyro sensor. Since theposture y₁(t) includes the high-frequency noise n₁(t), thehigh-frequency noise n₁(t) is cut from the posture y₁(t) by causing theposture y₁(t) to pass through a low pass filter 11. In contrast, sincethe posture y₂(t) includes the low-frequency noise n₂(t), thelow-frequency noise n₂(t) is cut from the posture y₂(t) by causing theposture y₂(t) to pass through a high pass filter 13. For example, thelow pass filter 11 and the high pass filter 13 are complementaryfilters. Therefore, an original signal with no noise is obtained byadding an output value of the low pass filter 11 and an output value ofthe high pass filter 13 as follows.G(s)x(t)+(1−G(s))x(t)=x(t)  [Math. 1]

FIG. 2 is an explanatory diagram for explaining a second example ofposture estimation using a combination of a gyro sensor and anacceleration sensor. Referring to FIG. 2, the posture y₁(t) iscalculated from the acceleration that is detected by the accelerationsensor, and the posture y₂(t) is calculated from the angular velocitythat is detected by the gyro sensor in the same manner as in the examplein FIG. 1. In particular, the posture y₂(t) is subtracted from theposture y₁(t) instead of using the high pass filter 13, and a differenceobtained as a result (that is, n₁(t)−n₂(t)) is made to pass through thelow pass filter 11. As a result, a negative value of the low-frequencynoise n₂(t) is output. Then, the low-frequency noise n₂(t) is subtractedfrom the posture y₂(t), and as a result, the original signal with nonoise is obtained.y ₂(t)−n ₂(t)=(x(t)+n ₂(t))−n ₂(t)=x(t)  [Math. 1]

In addition, it is possible to eliminate a delay at the high pass filter13 by not using the high pass filter 13 as described above.

(3) Position Estimation

(a) Position Estimation Using Inertial Sensor

Based on the posture calculated as described above, the accelerationthat is detected by the acceleration sensor (that is, acceleration in acoordinate system of the acceleration sensor) is converted into anacceleration in a ground coordinate system (for example, accelerationfrom the ground).

Furthermore, a variation in the velocity of the flight vehicle iscalculated by integrating the acceleration after the conversion.Therefore, the velocity of the flight vehicle is calculated from aninitial value of the velocity of the flight vehicle and the variation inthe velocity of the flight vehicle.

Furthermore, a variation in the position of the flight vehicle iscalculated by integrating the velocity. Therefore, the position of theflight vehicle is calculated from an initial value of the position ofthe flight vehicle and the variation in the position of the flightvehicle.

The acceleration detected by the acceleration sensor includes noise.Therefore, errors in the position of the flight vehicle that iscalculated from the acceleration are accumulated over time.

(b) Sensor Fusion

In order to avoid the accumulation of errors as described above, highlyreliable position estimation is realized by a combination of theinertial sensor and another sensor. For example, position estimationusing a combination of the inertial sensor and a GPS receiver isrealized. Hereinafter, a condition example will be described withreference to FIG. 3.

FIG. 3 is an explanatory diagram for explaining an example of positionestimation using a combination of the inertial sensor and anothersensor. Referring to FIG. 3, acceleration a in the ground coordinatesystem is obtained by conversion of the acceleration that is detected bythe acceleration sensor. The acceleration a is corrected at a portion 21and is integrated at a portion 23, and as a result, a variation in thevelocity is calculated. The already calculated velocity v is correctedat the portion 21, and the above variation is made at the portion 23. Asa result, a velocity vu after updating is obtained. Also, the velocityvu after the updating is integrated at the portion 23, and as a result,a variation in the position is calculated. An already calculatedposition p is corrected at the portion 21, and the above variation ismade at the portion 23. As a result, a position p_(U) after updating isobtained. Furthermore, a difference (for example, p_(x)−p_(U)) betweenthe position p_(x) generated by using another sensor (for example, theGPS receiver) and the position p_(U) after the updating is calculated asan error e, and the error e is made to pass through a filter 25. As aresult, a correction value Δa of the acceleration, a correction value Δvof the velocity, and a correction value Δp of the position are output.Then, these correction values are used for the correction at the portion21. As described above, the inertial sensor is complemented by anothersensor (for example, the GPS receiver).

The processing at the filter 25 is represented as follows.Δa _(t) =Δa _(t-1) +k ₃ ΔteΔv _(t) =k ₂ ΔteΔp _(t) =Δp _(t-1) +k ₁ Δte[Math. 3]

Δa_(t), Δv_(t), and Δp_(t) are correction values after the updating, andΔa_(t-1), Δv_(t-1), and Δp_(t-1) are correction values before theupdating. k₁, k₂, and k₃ are represented as follows by using a timeconstant T_(c) of the filter 25.

$\begin{matrix}{{k_{1} = \frac{3}{T_{c}}},{k_{2} = \frac{3}{T_{c}^{2}}},{k_{3} = \frac{1}{T_{c}^{3}}}} & \left\lbrack {{Math}.\mspace{14mu} 4} \right\rbrack\end{matrix}$

2. OUTLINE CONFIGURATION OF SYSTEM

Next, an outline configuration of a system 1 according to the embodimentof the present disclosure will be described with reference to FIG. 4.FIG. 4 is an explanatory diagram illustrating an example of an outlineconfiguration of the system 1 according to the embodiment of the presentdisclosure. Referring to FIG. 4, the system 1 includes a flight vehicle100, a control device 200, and a piloting device 300.

(1) Flight Vehicle 100

The flight vehicle 100 is a device that is capable of flying. Forexample, the flight vehicle 100 can fly using a plurality of rotors (forexample, four rotors). For example, the flight vehicle 100 may performstationary hovering, movement (movement upward, movement downward,horizontal movement, and movement in an oblique direction, for example),and turning, for example by controlling rotation of the respectiverotors. The flight vehicle 100 may be a device that is capable of flyingby using a mechanism other than rotors.

For example, the flight vehicle 100 can estimate the posture and theposition of the flight vehicle 100 itself and control the flight basedon the posture and the position. For example, the flight vehicle 100automatically flies based on a designated flight route.

For example, the flight vehicle 100 communicates with other devices (forexample, a control device 200). The flight vehicle 100 may performdirect wireless communication with other devices or may communicate withother devices via a relay node by performing wireless communication withthe relay node.

For example, the flight vehicle 100 includes an imaging device and usesthe imaging device to capture images during flight. The flight vehicle100 may save the captured images generated by the image capturing or maysend the captured images to another device such as the control device200. The captured images may be stationary images or moving images.

(2) Control Device 200

The control device 200 is a device that executes control in relation tothe flight of the flight vehicle 100. For example, the control includesgeneration and provision of flight information for the flight vehicle100 (for example, information that indicates the flight route) and/orinstructions to the flight vehicle 100 (for example, an instruction fortaking off and/or an instruction for returning) and/or the like.

For example, the control device 200 communicates with the flight vehicle100. The control device 200 may perform direct wireless communicationwith the flight vehicle 100 or may communicate with the flight vehicle100 via the relay node.

For example, the control device 200 acquires the captured imagesgenerated by the flight vehicle 100 capturing the images and displaysthe captured images as needed. The captured images may be moving images,and the control device 200 may acquire and display the moving images asstreaming.

In one example, the control device 200 may be a portable device such asa laptop computer or a tablet terminal. In addition, it is a matter ofcourse that the control device 200 is not limited to these examples andmay be another type of device.

(3) Piloting Device 300

The piloting device 300 is a device that enables a user to pilot theflight vehicle 100. In one example, the piloting device 300 is aproportional system (or a propo).

For example, the piloting device 300 is connected to the control device200. The piloting device 300 generates control information in relationto operations of the flight vehicle in response to a manipulation by theuser and transmits the control information to the control device 200.The control device 200 may transmit the control information to theflight vehicle 100 or may generate different control information fromthe control information and transmit the different control informationto the flight vehicle 100.

3. CONFIGURATION OF FLIGHT VEHICLE

Next, an example of a configuration of the flight vehicle 100 accordingto the embodiment of the present disclosure will be described withreference to FIG. 5. FIG. 5 is a block diagram illustrating an exampleof the configuration of the flight vehicle 100 according to theembodiment of the present disclosure. Referring to FIG. 5, the flightvehicle 100 includes rotors 110, motors 120, a sensor unit 130, animaging unit 140, a storage unit 150, a wireless communication unit 160,a processing unit 170, and a battery 190.

(1) Rotors 110 and Motors 120

Rotors 110A to 110D cause the flight vehicle 100 to fly by generatinglifting force from rotation.

(2) Motors 120

Motors 120A to 120D cause the rotors 110A to 110D to rotate inaccordance with control by the processing unit 170 (control unit 181).For example, the motors 120 changes the rotational speed of the rotors110 in accordance with the control by the processing unit 170 (controlunit 181).

(2) Sensor Unit 130

The sensor unit 130 includes one or more sensors. For example, thesensor unit 130 includes an inertial sensor 131, a GPS receiver 133, abarometer 135, and an ultrasonic sensor 137.

For example, the inertial sensor 131 includes an acceleration sensor anda gyro sensor. The inertial sensor 131 may further include a geomagneticsensor.

The sensors included in the sensor unit 130 are not limited to theseexamples. The sensor unit 130 may not include one or more sensors(except for the inertial sensor 131) from among the aforementionedsensors. Also, the sensor unit 130 may include other sensors.

(3) Imaging Unit 140

The imaging unit 140 captures images and generates captured images. Thecaptured images may be stationary images or moving images. The capturedimages may be saved in the storage unit 150 or may be transmitted toanother device via the wireless communication unit 160.

The imaging unit 140 includes one or more imaging devices. Each of theone or more imaging devices includes a lens, an image sensor, and thelike. The one or more imaging devices may include an infrared imagingdevice and/or an omnidirectional imaging device.

(4) Storage Unit 150

The storage unit 150 stores various kinds of information. The storageunit 150 stores programs and/or various kinds of data for operations ofthe flight vehicle 100.

For example, the storage unit 150 includes a non-volatile memory (forexample, a memory card). The storage unit 150 may include a magneticstorage device (for example, a hard disk drive) instead of or inaddition to a non-volatile memory.

(5) Wireless Communication Unit 160

The wireless communication unit 160 performs wireless communication. Thewireless communication unit 160 may perform direct wirelesscommunication with other devices (for example, the control device 200)or may perform wireless communication with the relay node forcommunication with other devices.

For example, the wireless communication unit 160 includes an antenna, anRF (Radio Frequency) circuit, and/or a base band processor.

(6) Processing Unit 170

The processing unit 170 performs various kinds of processing of theflight vehicle 100. The processing unit 170 includes a selection unit171, an information acquisition unit 173, an information generation unit175, a posture estimation unit 177, a position estimation unit 179, anda control unit 181. The processing unit 170 can further includecomponents other than these components. That is, the processing unit 170can perform operations other than operations of these components.

For example, the processing unit 170 includes circuitries. Morespecifically, the processing unit 170 includes one or more integratedcircuits, for example. For example, the one or more integrated circuitshold programs for operations of the processing unit 170. For example,the selection unit 171, the information acquisition unit 173, theinformation generation unit 175, the posture estimation unit 177, theposition estimation unit 179, and the control unit 181 can beimplemented as the programs. The one or more integrated circuits mayinclude an SoC (System-on-a-Chip), a micro controller, and/or otherprocessors.

(a) Posture Estimation Unit 177

The posture estimation unit 177 estimates the posture of the flightvehicle 100.

For example, the posture estimation unit 177 acquires informationgenerated by using the inertial sensor 131 and estimates the posture ofthe flight vehicle 100 from the information. For example, theinformation represents information that indicates the angular velocitydetected by the gyro sensor included in the inertial sensor 131 andinformation that indicates the acceleration detected by the accelerationsensor included in the inertial sensor 131. The posture estimation ofthe flight vehicle 100 is as described above as the basic postureestimation, for example. Therefore, detailed description will be omittedhere.

(b) Position Estimation Unit 179

The position estimation unit 179 estimates the position of the flightvehicle 100. This point will be described later in detail.

(c) Control Unit 181

The control unit 181 performs control in relation to flight of theflight vehicle 100.

(c-1) Control of Rotors 110

For example, the control unit 181 controls rotation of the rotors 110.Specifically, the control unit 181 controls operations of the motors120, thereby controlling the rotation of the rotors 110, for example.

For example, the control unit 181 adjusts the respective rotationalspeeds of the rotors 110A, 110B, 110C, and 110D, thereby causing theflight vehicle 100 to perform stationary hovering, movement (movementupward, movement downward, horizontal movement, or movement in anoblique direction, for example), or turning.

More specifically, it is possible to change the posture (inclinations ofa roll axis, a pitch axis, and a yaw axis) of the flight vehicle 100 byadjusting the respective numbers of rotations of the rotors, forexample. Therefore, it is possible to incline the flight vehicle 100with respect to the roll axis and the pitch axis, and as a result,propulsion force in the horizontal direction is generated, and theflight vehicle 100 moves in the horizontal direction. Also, a movingvelocity in the up-down direction changes in accordance with an increaseor a decrease in the numbers of rotations of the rotors, for example.

(c-2) Posture Control of Flight Vehicle 100

For example, the control unit 181 controls the posture of the flightvehicle 100.

For example, the control unit 181 corrects an error between the postureof the flight vehicle 100 estimated by the posture estimation unit 177and a target posture. More specifically, the control unit 181 calculatesthe error and calculates rotation of the rotors 110 (or an operation ofthe motors 120) for correcting the error, for example. Then, the controlunit 181 controls the rotation of the rotors 110 as described above.

(c-3) Position Control of Flight Vehicle 100

For example, the control unit 181 controls the position of the flightvehicle 100.

Example of Control

For example, the control unit 181 moves the flight vehicle 100 from theposition of the flight vehicle 100 estimated by the position estimationunit 179 to a target position. More specifically, the control unit 181calculates movement from the position of the flight vehicle 100 to thetarget position and calculates a target posture that allows themovement, for example. Then, the control unit 181 corrects an errorbetween the posture of the flight vehicle 100 and the target posture asdescribed above.

Example of Acquisition of Target Position

In one example, the control unit 181 acquires one or more targetpositions from flight route information that the control unit 181 holds.The flight route information may indicate one or more target positions,or the control unit 181 may calculate one or more target positions fromthe flight route information.

In another example, the control device 200 may transmit information thatindicates target positions, and the control device unit 181 may acquirethe positions that indicate the target positions.

(c-4) Others

Operations of the selection unit 171, the information acquisition unit173, and the information generation unit 175 will be described later indetail along with operations of the position estimation unit 179.

(7) Battery 190

The battery 190 accumulates electric power for causing the flightvehicle 100 to operate. The battery 190 may be a primary battery capableonly of discharging or may be a secondary battery also capable of beingcharged.

4. POSITION ESTIMATION ACCORDING TO EMBODIMENT OF PRESENT DISCLOSURE

Next, an example of position estimation according to the embodiment ofthe present disclosure will be described.

(1) Plurality of Position Estimation Systems

According to the embodiment of the present disclosure, a plurality ofposition estimation systems for estimating the position of the flightvehicle 100 are prepared. For example, the plurality of positionestimation systems include at least one of a system using a GPSreceiver, a system using an imaging device installed on the flightvehicle 100, a system using an imaging device for imaging the flightvehicle 100, a system using a barometer, and a system using anultrasonic sensor.

(a) System Using GPS Receiver

For example, there is a system using a GPS receiver as a positionestimation system.

The GPS receiver estimates the position in response to reception ofsignals from a plurality of GPS satellites. That is, the GPS receivercalculates the latitude, the longitude, and the altitude in response toreception of the signals from the plurality of GPS satellites. Thus, theGPS receiver 133 of the flight vehicle 100 estimates the position of theflight vehicle 100. That is, the GPS receiver 133 of the flight vehicle100 calculates the latitude, the longitude, and the altitude of theflight vehicle 100.

(b) System Using Imaging Device Installed on Flight Vehicle 100

For example, there is a system using an imaging device installed on theflight vehicle 100 as a position estimation system.

(b-1) SLAM

For example, the system using the imaging device installed on the flightvehicle 100 includes SLAM (Simultaneous Localization and Mapping).

Monocular SLAM

For example, there is SLAM using a monocular imaging device(hereinafter, referred to as “monocular SLAM”). Monocular SLAM utilizesdisparity of a feature point in a captured image, which is generated bymovement, and simultaneously estimates the three-dimensional position ofthe feature point and the position and the posture of the camera.

Since it may become uncertain whether the feature point is present at afar position and has a large size or the feature point is present at aclose position and has a small size, this system requires presenting afeature point with a known size at the time of initialization. Sincedisparity of the feature point does not occur in a case where the flightvehicle 100 stays and turns at the same location, the distance to thefeature point becomes uncertain, and it can be difficult to estimate theposition and the posture by utilizing a new feature point.

In order to compensate for these weak points, the monocular imagingdevice is installed on the flight vehicle 100 such that an optical axisof the monocular imaging device coincides with an axis of the flightvehicle 100 in the up-down direction, for example. Furthermore, themonocular imaging device is installed on the flight vehicle 100 by usinga gimbal. That is, SLAM that uses a monocular imaging device installedon the flight vehicle 100 by using a gimbal such that the optical axiscoincides with the axis of the flight vehicle 100 in the up-downdirection (hereinafter, referred to as “monocular SLAM with a gimbal”)is prepared as the position estimation system. For example, the opticalaxis is a vertical axis. Hereinafter, specific examples of this pointwill be described with reference to FIGS. 6 and 7.

FIG. 6 is an explanatory diagram for explaining a first example ofimaging by the monocular imaging device installed on the flight vehicle100 by using a gimbal. Referring to FIG. 6, the flight vehicle 100 isillustrated. In this example, the monocular imaging device is installedon the upper side of the flight vehicle 100 by using a gimbal such thatan optical axis 41 coincides with the vertical axis (the axis in avertical direction 43). The use of the gimbal maintains the optical axis41 such that it coincides with the vertical axis even if the flightvehicle 100 inclines. Therefore, the monocular imaging device alwaysimages a range 45 in a direction opposite to the vertical direction 43.

FIG. 7 is an explanatory diagram for explaining a second example ofimaging by a monocular imaging device installed on the flight vehicle100 by using a gimbal. Referring to FIG. 7, the flight vehicle 100 isillustrated. In this example, the monocular imaging device is installedon the lower side of the flight vehicle 100 by using the gimbal suchthat the optical axis 41 coincides with the vertical axis (the axis inthe vertical direction 43). The use of the gimbal maintains the opticalaxis 41 such that it coincides with the vertical axis even if the flightvehicle 100 inclines. Therefore, the monocular imaging device alwaysimages a range 47 in the vertical direction 43.

By installing the monocular imaging device on the flight vehicle 100such that the optical axis coincides with the up-down direction of theflight vehicle 100 as described above, it is possible to allow turningat a single location, when it is difficult for disparity to be caused,to coincide with the roll axis and the pitch axis of the flight vehicle100, for example. The flight vehicle 100 causes inclination with respectto the roll axis and the pitch axis for moving, and the inclination iswithin a range of ±15 degrees. Accordingly, since there is a lowprobability that the feature point will have been replaced with a newone by the turning, it is difficult for estimation of the position tobecome difficult. Furthermore, the installation by using the gimbalmakes it possible to always image a range in the vertical direction or arange in a direction opposite to the vertical direction, for example.Therefore, a robustness of the position estimation can be improved.

If a texture pattern of a taking-off and landing location (for example,a heliport) of the flight vehicle 100 is stored in advance, for example,the taking-off and landing location can be used as the feature pointwith the known size when the flight vehicle 100 takes off. In thismanner, the position estimation can be performed more precisely.

Stereo SLAM

For example, there is SLAM using a stereo imaging device (hereinafter,referred to as “stereo SLAM”). Stereo SLAM utilizes disparity of twocameras and estimates the three-dimensional position of a feature point.Therefore, it is possible to estimate the position without movement ofthe flight vehicle 100. Also, it is possible to estimate the positionwithout a feature point with a known size.

Features of SLAM

According to the SLAM, errors in the estimated positions are accumulatedin accordance with the amount of movement. Therefore, drift can occur inthe same manner as in the inertial sensor if the flight vehicle 100moves a long distance. However, since the amount of errors can besmaller than that for the inertial sensor and the errors do not increaseif the same feature point is used, the SLAM can complement the positionestimation using the inertial sensor.

(b-2) Markers

For example, the system using the imaging device installed on the flightvehicle 100 includes a system of estimating the position of the flightvehicle based on known positions at which markers have been arranged anda captured image of the markers that is generated by the imaging deviceinstalled on the flight vehicle 100.

For example, a plurality of markers are installed in a specific area,and the respective positions of the plurality of markers are held inadvance in the flight vehicle 100. If the flight vehicle 100 flies inthe specific area, the imaging device installed on the flight vehicle100 captures an image, and the position of the flight vehicle 100 isestimated from the positions of the respective markers inside thecaptured image generated by the image capturing and the known positionsof the respective markers. In one example, the imaging device is anomnidirectional camera capable of performing omnidirectional imagecapturing. In one example, each of the plurality of markers is alight-emitting marker (for example, an issuing LED (Light-EmittingDiode)) and appears as a lighting lump in the captured image.Hereinafter, an arrangement example of the markers will be describedwith reference to FIG. 8.

FIG. 8 is an explanatory diagram for explaining an arrangement exampleof the markers. Referring to FIG. 8, an area 51 and the flight vehicle100 that flies in the area 51 are illustrated. In the area 51, fourmarkers 53 are arranged. The imaging device (for example, anomnidirectional camera) installed in the flight vehicle 100 captures animage, and as a result, images the four markers 53. Then, the positionof the flight vehicle 100 is estimated from the respective positions ofthe four markers 53 in the captured image and the known positions of thefour markers 53.

For example, a direction from the center in the image captured by theomnidirectional camera to each marker coincides with an actual directionfrom the omnidirectional camera to the marker. Therefore, a position(M_(i) ^(x), M_(i) ^(y)) of a marker i and an observation directionTheta (Greek letter), and an estimated position (x, y) of the flightvehicle 100 and an estimated direction alpha (Greek letter) arerepresented as follows.θ_(i)(x,y,α)=α−a tan 2(M _(i) ^(y) −y,M _(i) ^(x) −x)+v  [Math. 5]

Since there are three unknown numbers (that is, x, y, and alpha (Greekletter)) and there are four observation points (four markers), the threeunknown numbers are calculated by a non-linear optimization problem.

It is a matter of course that a method of calculating the estimatedposition (x, y) and the estimated direction alpha (Greek letter) is notlimited to the aforementioned example. In one example, a plurality ofcandidates for the estimated position (x, y) and the estimated directionalpha (Greek letter) may be prepared in advance, and the observationdirection theta (Greek letter) may be calculated from candidatesincluded in the plurality of candidates in accordance with theaforementioned equation. Then, a difference between the calculatedobservation direction and an actual observation direction obtained fromthe captured image may be calculated as an error, and further,likelihoods for the candidates may be calculated from the calculatederror. Then, one candidate may be selected from among the plurality ofcandidates based on the likelihood of each of the plurality ofcandidates, and the one candidate may be estimated as the position andthe direction of the flight vehicle 100. At this time, a particle filtermay be used.

There is a possibility that the light-emitting markers are lost in thecaptured image due to reflection of sunlight or the like in the outdoorspace. Cutting of visible light by a filter can also make it difficultto perform separation. Therefore, the light-emitting markers may have aspecific light-emitting pattern, for example. Then, the light-emittingmarkers with the specific light-emitting pattern may be detected in thecaptured image.

In the position estimation system as described above (that is, aposition estimation system based on the captured image of the markers),no errors are accumulated in proportion to time. Therefore, such aposition estimation system can complement the position estimation usingthe inertial sensor.

(c) System Using Imaging Device that Images Flight Vehicle

For example, there is a system using an imaging device that images theflight vehicle 100 as a position estimation system.

For example, the imaging device images the flight vehicle 100, and theposition and the motion of the flight vehicle 100 are calculated basedon the captured image in motion capturing. Hereinafter, an example of acase where the motion capturing is used will be described with referenceto FIG. 9.

FIG. 9 is an explanatory diagram for explaining an example of a casewhere the motion capturing is used. For example, an informationprocessing device 400 calculates the position and the motion of theflight vehicle 100 based on captured images generated by imaging devices410 and 420. Then, the information processing device 400 transmitsinformation that indicates the position (and the motion) to the flightvehicle 100. In one example, the information processing device 400transmits the information to the flight vehicle 100 via the controldevice 200. The information processing device 400 may transmit theinformation to the flight vehicle 100 directly or via a relay node. Inaddition, the information processing device 400 and the control device200 may be the same device.

In the position estimation system as described above (that is, thesystem using the imaging device that images the flight vehicle 100), noerrors are accumulated in proportion to time. Therefore, such a positionestimation system can complement the position estimation using theinertial sensor.

(d) System Using Barometer

For example, there is a system using a barometer as a positionestimation system.

For example, the altitude of the flight vehicle 100 is estimated fromthe atmospheric pressure measured by the barometer 135 of the flightvehicle 100. Specifically, the altitude corresponding to the atmosphericpressure estimated by the barometer 135 of the flight vehicle 100 isestimated as the altitude of the flight vehicle 100.

In the system using the barometer, no errors are accumulated inproportion to time. Therefore, the position estimation system cancomplement the position estimation using the inertial sensor.

(e) System Using Ultrasonic Sensor

For example, there is a system using an ultrasonic sensor as a positionestimation system.

For example, the ultrasonic sensor 137 of the flight vehicle 100 emitsan ultrasonic wave in the vertical direction and receives a reflectedwave of the ultrasonic wave. Then, the altitude of the flight vehicle100 is estimated from a time from the emission of the ultrasonic wave tothe reception of the reflected wave.

In the system using the ultrasonic sensor, no errors are accumulated inproportion to time. Therefore, the position estimation system cancomplement the position estimation using the inertial sensor.

(f) Features of Respective Systems

The aforementioned position estimation systems have respectivelydifferent features. Hereinafter, a specific example of this point willbe described with reference to FIG. 10.

FIG. 10 is an explanatory diagram for explaining features of therespective position estimation systems. Referring to FIG. 10, precision(resolution and/or an error in the position), a sampling frequency, atime delay, a filter time constant, a use environment, and compatibilitywith the inertial sensor of each position estimation system are shown.The time delay is a time delay that accompanies the position estimation.The filter time constant is a time constant of the filter that is usedto calculate the correction values and is a value in accordance withnoise properties of the position estimation. In the system using the GPSreceiver, for example, the precision ranges from 5 to 10 meters, thesampling frequency ranges from 2 to 5 Hz, and the time delay thataccompanies the position estimation ranges from 400 to 600 milliseconds.In the monocular SLAM, the precision is several centimeters, thesampling frequency is about 30 Hz, and the time delay that accompaniesthe position estimation ranges from 30 to 100 milliseconds. In thismanner, the precision, the cycle, the time delay, the filter timeconstant, the use environment, the compatibility with the inertialsensor, and the like differ depending on the position estimation system.

(2) Selection of Position Estimation System and Position Estimation

The information acquisition unit 173 acquires information that indicatesa position estimation system selected from the plurality of positionestimation systems for estimating the position of the flight vehicle100. The position estimation unit 179 estimates the position of theflight vehicle 100 from first information that is generated by using theinertial sensor 131 of the flight vehicle 100 and second informationthat is generated through the position estimation system based onparameters for the position estimation system.

(a) Plurality of Position Estimation Systems

For example, the plurality of position estimation systems include atleast one of the system using the GPS receiver, the system using theimaging device installed on the fight vehicle 100, the system using theimaging device for imaging the flight vehicle 100, the system using thebarometer, and the system using the ultrasonic sensor. These positionestimation systems are as described above.

(b) Acquisition of Information that Indicates Position Estimation System

In a first example, the selection unit 171 dynamically selects aposition estimation system from among the plurality of positionestimation system as will be described later. Then, the informationacquisition unit 173 acquires information that indicates the positionestimation system.

In a second example, the user may select a position estimation systemfrom among the plurality of position estimation systems in a staticmanner, and information that indicates the position estimation systemmay be held by the flight vehicle 100. The information acquisition unit173 may then acquire the information.

For example, the information that indicates the position estimationsystem is identification information of the position estimation system.

(c) First Information Generated by Using Inertial Sensor 131

For example, the inertial sensor 131 includes an acceleration sensor,and the first information that is generated by using the inertial sensor131 includes information that indicates acceleration of the flightvehicle 100.

For example, the first information that is generated by using theinertial sensor 131 further includes information that indicates theposture of the flight vehicle 100. The posture is estimated by theposture estimation unit 177 as described above.

(d) Second Information Generated Through Position Estimation System

For example, the second information that is generated through theposition estimation system is information that indicates the position ofthe flight vehicle 100.

(d-1) First Example: Case of System Using GPS Receiver

In a first example, the position estimation system is a system using aGPS receiver. In this case, the information generation unit 175 acquiresoutput information (information that indicates the latitude, thelongitude, and the altitude of the fight vehicle 100) of the GPSreceiver 133 and generates the second information that indicates theposition of the flight vehicle 100 (for example, information thatindicates the position of the flight vehicle 100 with respect to apredetermined position as an origin) from the output information, forexample. Then, the position estimation unit 179 acquires the secondinformation.

(d-2) Second Example: Case of System Using Imaging Device Installed onFlight Vehicle 100

In a second example, the position estimation system is a system using animaging device that is installed on the flight vehicle 100 (for example,a position estimation system based on SLAM or a marker captured image).In this case, the information generation unit 175 acquires the capturedimage generated by the imaging device included in the imaging unit 140and generates the second information that indicates the position of theflight vehicle 100, based on the captured image, for example. Then, theposition estimation unit 179 acquires the second information.

(d-3) Third Example: Case of System Using Imaging Device for ImagingFlight Vehicle 100

In a third example, the position estimation system is a system using animaging device for imaging the flight vehicle 100. Referring again toFIG. 9, the information processing device 400 generates the secondinformation that indicates the position of the flight vehicle 100, andthe second information is transmitted to the flight vehicle 100, forexample. Then, the position estimation unit 179 acquires the secondinformation.

(d-4) Fourth Example: Case of System Using Barometer

In a fourth example, the position estimation system is a system using abarometer. In this case, the information generation unit 175 acquiresoutput information (information that indicates an atmospheric pressure)of the barometer 135 and generates the second information that indicatesthe position of the flight vehicle 100 (for example, information thatindicates the altitude of the flight vehicle 100) from the outputinformation. Then, the position estimation unit 179 acquires the secondinformation.

(d-5) Fifth Example: System Using Ultrasonic Sensor

In a fifth example, the position estimation system is a system using anultrasonic sensor. In this case, the position estimation unit 179acquires output information (information that indicates a distance) ofthe ultrasonic sensor 137 as the second information that indicates theposition of the flight vehicle 100 (for example, information thatindicates the altitude of the flight vehicle 100), for example.

(e) Position Estimation Based on Parameters

(e-1) Holding of Parameters

For example, parameters for each of the plurality of position estimationsystems are held by the flight vehicle 100. In one example, a tableincluding the parameters for each of the plurality of positionestimation systems is held. Then, the position estimation unit 179acquires the parameters held.

(e-2) Examples of Parameters: Parameter Related to Time Delay

For example, the parameters for the position estimation systems includea parameter related to a time delay that accompanies the positionestimation by the position estimation system (hereinafter, referred toas a “time delay parameter”).

Example of Time Delay Parameter

In one example, the time delay parameter is the time delay thataccompanies the position estimation by the position estimation system.In another example, the time delay parameter may be a difference betweenthe time delay that accompanies the position estimation by the positionestimation system and a time delay that accompanies the positionestimation using the inertial sensor. An example of the time delay ofeach position estimation system is as described above with reference toFIG. 10.

Example of Position Estimation

For example, the position estimation unit 179 calculates the correctionvalues from the second information generated through the positionestimation system based on the time delay parameter. Then, the positionestimation unit 179 estimates the position of the flight vehicle 100from the first position that is generated by using the inertial sensor131 and the correction values.

More specifically, the position estimation unit 179 acquires thirdinformation that indicates the position of the flight vehicle 100, whichhas already been estimated, based on the time delay parameter. Then, theposition estimation unit 179 calculates the correction values from thesecond information that is generated through the position estimationsystem and the third information. Hereinafter, a specific example willbe described with reference to FIGS. 3 and 11.

Referring again to FIG. 3, the position estimation unit 179 acquiresinformation that indicates an acceleration a as the first information(the information that is generated by using the inertial sensor 131),for example. Then, the position estimation unit 179 estimates theposition p_(U) of the flight vehicle from the information that indicatesthe acceleration a and the correction values (the correction value Δa ofthe acceleration, the correction value Δv of the velocity, and thecorrection value Δ of the position) output by the filter 25. Inaddition, the position estimation unit 179 acquires the information thatindicates the position p_(x) as the second information that is generatedthrough the position estimation system and acquires information thatindicates the position p_(U) as the third information that indicates theposition of the flight vehicle 100, which has already been estimated.Then, the position estimation unit 179 calculates a difference betweenthe position p_(x) and the position p_(U) as an error e from theinformation that indicates the position p_(x) and the information thatindicates the position p_(U) and causes the error e to pass through thefilter 25, thereby calculating the correction values (the correctionvalue Δa of the acceleration, the correction value Δv of the velocity,and the correction value Δ of the position). In particular, the positionestimation unit 179 acquires the information that indicates the positionp_(U) (third information) based on the parameter related to the timedelay that accompanies the position estimation by the positionestimation system (that is, the time delay parameter).

FIG. 11 is an explanatory diagram for explaining an example of positionestimation based on the time delay parameter. Referring to FIG. 11,third information 61 that indicates the position p_(U) of the flightvehicle 100 and second information 63 that is generated through theposition estimation system (information that indicates the positionp_(x)) are illustrated. For example, a time delay 65 that accompaniesthe position estimation using the inertial sensor 131 (that is, a timedelay that accompanies generation of the third information 61) issignificantly shorter than a time delay 67 (that is, a time delay thataccompanies generation of the second information) that accompaniesposition estimation by the position estimation system (for example, thesystem using the GPS receiver). Therefore, if second information 63Aobtained at time T3 and third information 61F as the latest informationat that time are simply acquired and the difference between the positionp_(x) that is indicated by the second information 63A and the positionp_(U) that is indicated by the third information 61F is calculated asthe error e, the error e can be an inappropriate value. That is, theerror in the positions at different times is calculated as the error e.Thus, the position estimation unit 179 acquires the third information61A that indicates the position per time T1 preceding time T3 by thetime delay 67 and the second information 63A based on the parameter thatindicates the time delay 67 (or the parameter that indicates thedifference between the time delay 67 and the time delay 65), forexample. Then, the position estimation unit 179 calculates, as the errore, a difference between the position p_(x) that is indicated by thesecond information 63A and the position p_(U) that is indicated by thethird information 61A. Similarly, the position estimation unit 179acquires third information 61F that indicates the position per time T2and second information 63B. Then, the position estimation unit 179calculates, as the error e, a difference between the position p_(x) thatis indicated by the second information 63B and the position p_(U) thatis indicated by the third information 61F. The position p_(U) (that is,the third information 61) is held for a period corresponding at least tothe time delay 67 in order to calculate the error e.

The position of the flight vehicle 100 is estimated based on the timedelay parameter for the position estimation system as described above,for example. In this manner, appropriate correction values suitable forthe position estimation system are calculated, for example. As a result,the position of the flight vehicle 100 can be more favorably estimated.Hereinafter, specific examples of this point will be described withreference to FIGS. 12 and 13.

FIG. 12 is an explanatory diagram for explaining an example of a resultof position estimation without using the time delay parameter. In thisexample, the system using the GPS receiver is used as the positionestimation system. A position 1010 that is estimated by using theinertial sensor varies in accordance with movement of the flight vehicle100. In contrast, a position 1020 estimated by using the GPS receiverdoes not vary immediately after the movement of the flight vehicle 100.Since the position estimation is performed without using the time delayparameter for the position estimation system (that is, the system usingthe GPS receiver) in this example, an estimation position 1030 isreturned to the original position due to the position 1020 that does notvary.

FIG. 13 is an explanatory diagram for explaining an example of a resultof position estimation based on the time delay parameter. In thisexample, the system using the GPS receiver is also used as the positionestimation system. The position 1010 that is estimated by using theinertial sensor varies in accordance with movement of the flight vehicle100. In contrast, the position 1020 that is estimated by using the GPSreceiver does not vary immediately after the movement of the flightvehicle 100. Since the position estimation is performed based on thetime delay parameter for the position estimation system (that is, thesystem using the GPS receiver) in this example, returning of theestimation position 1030 due to the position 1020 that does not vary isreduced, and a favorably estimated position 1030 is obtained.

(e-3) Example of Parameter: Parameter Related to Noise Properties

For example, the parameters for the position estimation system includesa parameter related to properties of noise that accompanies the positionestimation by the position estimation system (hereinafter, referred toas a “noise property parameter”).

Example of Noise Property Parameter

In one example, the noise property parameter is a time constant of afilter that is used to calculate the correction values. Referring againto FIG. 3, the noise property parameter is a time constant of the filter25, for example. The example of the filter time constant of eachposition estimation system is as described above with reference to FIG.10.

In another example, the noise property parameter may be a band of thenoise. Then, the time constant of the filter may be calculated from thenoise property parameter (the band of the noise).

Example of Position Estimation

For example, the position estimation unit 179 calculates the correctionvalues from the second information that is generated through theposition estimation system based on the noise property parameter. Then,the position estimation unit 179 estimates the position of the flightvehicle 100 from the first information that is generated by using theinertial sensor 131 and the correction values.

Referring again to FIG. 3, the time constant (that is, the noiseproperty parameter) for the position estimation system selected fromamong the plurality of position estimation systems is set as a timeconstant T_(c) of the filter 25, for example. The time constant is atime constant corresponding to a property of the noise that accompaniesthe position estimation by the position estimation system. The positionestimation unit 179 acquires information that indicates the positionp_(x) as the second information that is generated through the positionestimation system and calculates, as the error e, a difference betweenthe position p_(x) and the position p_(U) of the flight vehicle 100,which has already been estimated. Then, the position estimation unit 179causes the error e to pass through the filter 25 (time constantT_(c)=noise property parameter), thereby calculating the correctionvalues (the correction value Δa of acceleration, the correction value Δvof the velocity, and the correction value Δ of the position). Then, theposition estimation unit 179 estimates the position p_(U) of the flightvehicle 100 from the first information (for example, information thatindicates the acceleration a) that is generated by using the inertialsensor 131 and the correction values.

For example, the position of the flight vehicle 100 is estimated basedon the noise property parameter for the position estimation system asdescribed above. In this manner, appropriate correction values suitablefor the position estimation system are calculated, for example. As aresult, the position of the flight vehicle can be more favorablyestimated.

As described above, the position estimation unit 179 estimates theposition of the flight vehicle 100 based on the parameter for theposition estimation system selected from among the plurality of positionestimation systems. In this manner, it is possible to apply not only theposition estimation system using the GPS receiver but also anotherposition estimation system, for example. Therefore, it is possible tomore favorably estimate the position of the flight vehicle 100 even ifit is difficult to estimate the position by the GPS receiver. Inaddition, since features (for example, a time delay and/or a noiseproperty) of the position estimation system are reflected in theposition estimation even if the position estimation system is switchedbetween the plurality of position estimation systems, the position ofthe flight vehicle 100 can be more favorably estimated. In addition, itis possible to more easily switch the position estimation system betweenthe plurality of position estimation systems.

(3) Dynamic Selection of Position Estimation System

For example, the selection unit 171 dynamically selects the positionestimation system from among the plurality of position estimationsystems during flight of the flight vehicle 100. That is, the positionestimation system is switched between the plurality of positionestimation systems during flight of the flight vehicle 100.

(a) Transfer of Initial Value

If a new position estimation system is selected, for example, theinitial value of the position estimation is provided for the positionestimation by the new position estimation system.

(a-1) Operation of Respective Components

For example, the selection unit 171 selects a first position estimationsystem from among the plurality of position estimation systems. Then,the information acquisition unit 173 acquires information that indicatesthe first position estimation system. Then, the position estimation unit179 estimates the position of the flight vehicle 100 from firstinformation that is generated by using the inertial sensor 131 andsecond information that is generated through the first positionestimation system based on the parameter for the first positionestimation system.

Furthermore, the selection unit 171 selects a second position estimationsystem from among the plurality of position estimation systems after theselection of the first position estimation system. In particular, theselection unit 171 provides the estimated position as an initial valueof the position estimation by the second position estimation system. Forexample, the information generation unit 175 performs the positionestimation by the second position estimation system, and the selectionunit 171 provides the estimated position as the initial value to theinformation generation unit 175.

Then, the information acquisition unit 173 acquires information thatindicates the second position estimation system. Thereafter, theposition estimation unit 179 estimates the position of the flightvehicle 100 from the first information that is generated by using theinertial sensor 131 and the second information that is generated throughthe second position estimation system based on the parameter for thesecond position estimation system.

(a-2) Example of Position Estimation System

For example, the second position estimation system is a system forestimating a relative position of the first vehicle 100. Morespecifically, the second position estimation system is a system using animaging device that is installed on the flight vehicle 100 (for example,a position estimation system based on SLAM or a captured image ofmarkers), for example.

For example, the first position estimation system is a system forestimating an absolute position of the flight vehicle 100. Morespecifically, the first position estimation system is a system using aGPS receiver, a system using an imaging device for imaging the flightvehicle 100, a system using a barometer, or a system using an ultrasonicsensor. In addition, the first position estimation system may also be asystem for estimating the relative position of the flight vehicle 100.

(a-3) Specific Example

Referring again to FIG. 3, the selection unit 171 selects the firstposition estimation system (for example, the system using the GPSreceiver), for example. Then, the position estimation unit 179 estimatesthe position p_(U) of the flight vehicle 100 from the first information(for example, the information that indicates the acceleration a) that isgenerated by using the inertial sensor 131 and the second information(the information that indicates the position p_(x)) that is generatedthrough the first position estimation system. Thereafter, the selectionunit 171 selects the second position estimation system (for example, theSLAM) and provides the position p_(U) as an initial value of theposition estimation by the second position estimation system to theinformation generation unit 175. Then, the information generation unit175 sets the position p_(U) as the initial value of the positionestimation by the second position estimation system and generates thesecond information (the information that indicates the position p_(x))through the second position estimation system. Then, the positionestimation unit 179 estimates the position p_(U) of the flight vehicle100 from the first position (for example, the information that indicatesthe acceleration a) that is generated by using the inertial sensor 131and the second information (the information that indicates the positionp_(x)) that is generated by the information generation unit 175 throughthe second position estimation system.

(a-4) Others

If the second position estimation system is a system for estimating theabsolute position of the flight vehicle 100 (for example, the systemusing the GPS receiver), for example, the selection unit 171 does notprovide the estimated position as the initial value of the positionestimation by the second position estimation system.

The selection unit 171 may provide the posture of the flight vehicle 100that is estimated by the posture estimation unit 177 as an initial valueof the posture for the position estimation by the second positionestimation system in addition to the estimated position of the flightvehicle 100.

If the new position estimation system is selected as described above,for example, the initial value of the position estimation is providedfor the position estimation by the new position estimation system. Inthis manner, it is possible to perform seamless position estimation, forexample. Also, it is possible to transfer the position estimation valueobtained by the system for estimating the absolute position to thesystem for estimating the relative position. Also, since the positionestimation value obtained by the system for estimating the relativeposition is reset every time the selection is made, accumulation oferrors can be reduced,

(b) Trigger of Selection

(b-1) Position Condition

For example, the selection unit 171 newly selects the positionestimation system from among the plurality of position estimationsystems if the position of the flight vehicle 100 meets a predeterminedposition condition.

More specifically, the selection unit 171 newly selects the positionestimation system from among the plurality of position estimationsystems if the position of the flight vehicle 100 coincides with apredetermined switching position, for example. Hereinafter, specificexamples will be described with reference to FIGS. 14 to 16.

First Example

FIG. 14 is an explanatory diagram for explaining a first example ofselection (switching) the position estimation system. Referring to FIG.14, a bridge 71 is illustrated. In this example, the flight vehicle 100flies along a route from Start to Goal to image the entire rear side ofthe bridge 71. That is, the flight vehicle 100 reciprocates between anarea 75 to which sufficient radio waves reaches from a GPS satellite 73and an area 77 to which the radio waves from the GPS satellite 73 do noteasily reach. In this case, the selection unit 171 newly selects theSLAM (for example, the stereo SLAM) as the position estimation systemwhen the flight vehicle 100 enters the area 77 from the area 75. Thatis, the selection unit 171 newly selects the SLAM (for example, thestereo SLAM) as the position estimation system when the position of theflight vehicle 100 coincides with a position of a boundary between thearea 75 and the area 77 (or a position near the boundary). Here, thealready estimated position is transferred as an initial value of theposition estimation by the SLAM. Also, the already estimated posture canalso be transferred as the initial value of the posture for the positionestimation by the SLAM. In contrast, the selection unit 171 newlyselects the system using the GPS as the position estimation system whenthe flight vehicle 100 enters the area 75 from the area 77. That is, theselection unit 171 newly selects the system using the GPS as theposition estimation system when the position of the flight vehicle 100coincides with the position of the boundary between the area 77 and thearea 75 (or the position near the boundary). The switching of theposition estimation system (that is, the switching between the systemusing the GPS and the SLAM) is performed in this manner.

The position estimation system can also be selected in the same mannerwhen the flight vehicle 100 reciprocates between an indoor space and anoutdoor space.

Second Example

FIG. 15 is an explanatory diagram for explaining a second example ofselection (switching) of the position estimation system. Referring toFIG. 15, tall buildings 81 are illustrated. In this example, the flightvehicle 100 flies along a route including a path between the tallbuildings 81. That is, the flight vehicle 100 flies in an area 83 towhich sufficient radio waves reaches from a GPS satellite and an area 85to which the radio waves from the GPS satellite do not easily reach(that is, an area between the tall buildings 81). In this case, thesection unit 171 newly selects the SLAM (for example, the stereo SLAM)as the position estimation system when the flight vehicle 100 enters thearea 85 from the area 83. That is, the selection unit 171 newly selectsthe SLAM (for example, the stereo SLAM) as the position estimationsystem when the position of the flight vehicle 100 coincides with aposition of a boundary between the area 83 and the area 85 (or aposition near the boundary). Here, the already estimated position istransferred as an initial value of the position estimation by the SLAM.The already estimated posture can also be transferred as an initialvalue of the posture for the position estimation by the SLAM. Incontrast, the selection unit 171 newly selects the system using the GPSas the position estimation system when the flight vehicle 100 enters thearea 83 from the area 85. That is, the selection unit 171 newly selectsthe system using the GPS as the position estimation system when theposition of the flight vehicle 100 coincides with the position of theboundary between the area 85 and the area 83 (or the position near theboundary). The switching of the position estimation system (that is, theswitching between the system using the GPS and the SLAM) is performed inthis manner.

The position estimation system can also be selected in the same mannerwhen the flight vehicle 100 flies in a valley of a mountain.

Third Example

FIG. 16 is an explanatory diagram for explaining a third example ofselection (switching) of the position estimation system. Referring toFIG. 16, a sports ground 91 is illustrated. Markers 93 are arranged inthe sports ground 91. In this example, the flight vehicle 100 fliesinside and outside the sports ground 91. That is, the flight vehicle 100flies in an area in which the markers 93 cannot be imaged and an area 97in which the markers 93 can be imaged. In this case, the selection unit171 newly selects the position estimation system based on the capturedimage of the markers as the position estimation system when the flightvehicle 100 enters the area 97 from the area 95. That is, the selectionunit 171 newly selects the position estimation system based on thecaptured image of the markers as the position estimation system when theposition of the flight vehicle 100 coincides with a position of aboundary between the area 95 and the area 97 (or a position near theboundary). Here, the already estimated position is transferred as aninitial value of the position estimation based on the captured image ofthe markers. Also, the already estimated posture can be transferred asan initial value of the posture for the position estimation based on thecaptured image of the markers. In contrast, the selection unit 171 newlyselects the system using the GPS as the position estimation system whenthe flight vehicle 100 enters the area 95 from the area 97. That is, theselection unit 171 newly selects the system using the GPS as theposition estimation system when the position of the flight vehicle 100coincides with the position of the boundary between the area 97 and thearea 95 (or the position near the boundary). The switching of theposition estimation system (that is, the switching between the systemusing the GPS and the position estimation system based on the capturedimage of the markers) is performed in this manner.

In addition, the position estimation system can also be selected in thesame manner when the flight vehicle 100 reciprocates between an indoorspace where markers are arranged and an outdoor space where no markersare arranged.

The position estimation system is newly selected when the position ofthe flight vehicle 100 meets the predetermined position condition asdescribed above. In this manner, it is possible to automatically switchthe position estimation system at a desired position. Therefore, it ispossible to apply an appropriate position estimation system inaccordance with an area where the flight vehicle 100 is located.

(b-2) Reliability of Position Estimation System

The selection unit 171 may select the position estimation system fromamong the plurality of position estimation systems based on areliability that is dynamically calculated for each of the plurality ofposition estimation systems.

The reliability of each of the plurality of position estimation systemsmay be normalized (to a numerical value of 0 to 100, for example). Then,the selection unit 171 may newly select another position estimationsystem when the reliability calculated for the current positionestimation system is lower than the reliability calculated for anotherposition estimation system.

The reliability of the system using the GPS receiver may be calculatedbased on a status of capturing the GPS satellites (for example, thenumber of GPS satellites from which signals are received and/or thereception sensitivity of signals transmitted from the GPS satellites).The reliability of the SLAM may be calculated based on the number offeature points. The reliability of the position estimation system basedon the captured image of the markers may be calculated based on a markerdetection status.

In this manner, a position estimation system with higher reliability isapplied, and the precision of the position estimation can be improved,for example.

For example, the position estimation system is dynamically selected fromamong the plurality of position estimation systems during flight of theflight vehicle 100 as described above. In this manner, the position ofthe flight vehicle 100 can be more favorably estimated when the flightvehicle 100 flies in various areas, for example.

(4) Combination Usage of Position Estimation Systems

The information acquisition unit 173 may acquire information thatindicates two or more position estimation systems selected from amongthe plurality of position estimation systems. Then, the positionestimation unit 179 may estimate the position of the flight vehicle 100from first information that is generated by using the inertial sensor131 and second information that is generated through each of the two ormore position estimation systems based on a parameter for each of thetwo or more position estimation systems. That is, two or more positionestimation systems may be used in combination.

For example, the second information that is generated through each ofthe two or more position estimation systems is information thatindicates the position of the flight vehicle 100.

In one example, the position estimation unit 179 may calculate anaverage of the positions that are estimated through the two or moreposition estimation systems (that is, an average position). Then, theposition estimation unit 179 may estimate the position of the flightvehicle 100 from the first information and the information thatindicates the average (that is, the average position).

In another example, the position estimation unit 179 may multiply theposition that is estimated through the position estimation systems by aweight corresponding to the position estimation system, for each of thetwo or more position estimation systems. Then, the position estimationunit 179 may calculate a sum of the weighted positions for the two ormore position estimation systems. Then, the position estimation unit 179may estimate the position of the flight vehicle 100 from the firstinformation and information that indicates the sum. The weightcorresponding to the position estimation system may be a reliability ofthe position estimation system.

In this manner, precision of the position estimation can be improved,for example.

5. FLOW OF PROCESSING

Next, an example of processing according to the embodiment of thepresent disclosure will be described with reference to FIGS. 17 to 19.

(1) Position Estimation Processing

FIG. 17 is a flowchart illustrating an example of an outline flow ofposition estimation processing according to the embodiment of thepresent disclosure.

The information acquisition unit 173 acquires information that indicatesthe position estimation system selected from among the plurality ofposition estimation systems for estimating the position of the flightvehicle 100 (S501).

The position estimation unit 179 acquires and applies a parameter forthe position estimation system (S503).

The position estimation unit 179 estimates the position of the flightvehicle 100 from the first information that is generated by using theinertial sensor 131 of the flight vehicle 100 and the second informationthat is generated through the position estimation system (S505). Then,the processing repeats Step S505.

(2) Selection Processing

(a) First Example

FIG. 18 is a flowchart illustrating an example of an outline flow offirst selection processing according to the embodiment of the presentdisclosure.

The selection unit 171 acquires information that indicates the positionof the flight vehicle 100 (S521). For example, the position is aposition estimated by the position estimation unit 179.

If the position of the flight vehicle 100 meets the predeterminedposition condition (S523: YES), the selection unit 171 newly selects theposition estimation system from among the plurality of positionestimation systems (S525). Then, the selection unit 171 provides theposition of the flight vehicle 100 (for example, the position estimatedby the position estimation unit 179) as an initial value of the positionestimation by the position estimation system (S527). Then, theprocessing returns to Step S521.

If the position of the flight vehicle 100 does not meet thepredetermined position condition (S523: NO), the processing returns toStep S521.

(b) Second Example

FIG. 19 is a flowchart illustrating an example of an outline flow ofsecond selection processing according to the embodiment of the presentdisclosure.

The selection unit 171 acquires information that indicates a reliabilityof each of the plurality of position estimation systems (S541).

If a reliability of another estimation system is higher than thereliability of the current position estimation system (S543: YES), theselection unit 171 newly selects another position estimation system(S545). Then, the selection unit 171 provides the position of the flightvehicle 100 (for example, the position estimated by the positionestimation unit 179) as an initial value of the position estimation byanother position estimation system (S547). Then, the processing returnsto Step S541.

If the reliability of the current position estimation system is higherthan the reliability of another position estimation system (S543: NO),the processing returns to Step S541.

6. CONCLUSION

The flight vehicle 100 and the respective processing according to theembodiment of the present disclosure were described hitherto withreference to FIGS. 1 to 19. According to the embodiment of the presentdisclosure, the flight vehicle 100 includes the information acquisitionunit 173 that acquires information that indicates the positionestimation system selected from among the plurality of positionestimation systems for estimating the position of the flight vehicle 100and the position estimation unit 179 that estimates the position of theflight vehicle 100 from the first information that is generated by usingthe inertial sensor 131 of the flight vehicle 100 and the secondinformation that is generated through the position estimation systembased on the parameter for the position estimation system. In thismanner, it is possible to more favorably estimate the position of theflight vehicle 100, for example.

Also, a module for the flight vehicle 100 may include the informationacquisition unit 173 and the position estimation unit 179 (and one ormore other components included in the processing unit 170).

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

For example, the processing steps in the processing described herein maynot necessarily be executed in a chronological manner in the ordersdescribed in the flowcharts or sequence diagrams. For example, theprocessing steps in the processing may be executed in an order differentfrom those described in the flowcharts or the sequence diagrams or maybe executed in parallel.

Also it is possible to produce a computer program (in other words, acomputer program for causing a processor to execute the operations ofthe components of the device) for causing the processor (for example, aCPU or a DSP) provided in the device (for example, a flight vehicle or amodule for the flight vehicle) described herein to function as thecomponents (for example, the selection unit 171, the informationacquisition unit 173, the information generation unit 175, the postureestimation unit 177, the position estimation unit 179 and/or the controlunit 181) of the device. Also, a recording medium that records thecomputer program may be provided. Moreover, a device (for example, aflight vehicle or a module for the flight vehicle) that includes amemory that stores the computer program and one or more processors thatis capable of executing the computer program may also be provided.Moreover, a method that includes the operations of the components (forexample, the selection unit 171, the information acquisition unit 173,the information generation unit 175, the posture estimation unit 177,the position estimation unit 179, and/or the control unit 181) of thedevice is also included in the technology according to the disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art based on the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A device including:

an acquisition unit that acquires information indicating a positionestimation system selected from among a plurality of position estimationsystems for estimating a position of a flight vehicle; and

a position estimation unit that estimates the position of the flightvehicle from first information generated by using an inertial sensor ofthe flight vehicle and second information generated through the positionestimation system based on a parameter for the position estimationsystem.

(2)

The device according to (1),

wherein the parameter includes a parameter related to a time delay thataccompanies the position estimation by the position estimation system.

(3)

The device according to (2),

wherein the position estimation unit calculates a correction value fromthe second information based on the parameter related to the time delayand estimates the position of the flight vehicle from the firstinformation and the correction value.

(4)

The device according to (3),

wherein the position estimation unit acquires third information thatindicates the position of the flight vehicle, which has already beenestimated, based on the parameter related to the time delay andcalculates the correction value from the second information and thethird information.

(5)

The device according to any one of (1) to (4),

wherein the parameter includes a parameter related to a property ofnoise that accompanies the position estimation by the positionestimation system.

(6)

The device according to (5),

wherein the position estimation unit calculates a correction value fromthe second information based on the parameter related to the property ofthe noise and estimates the position of the flight vehicle from thefirst information and the correction value.

(7)

The device according to (6),

wherein the parameter related to the noise is a time constant of afilter that is used for calculating the correction value.

(8)

The device according to any one of (1) to (7),

wherein the plurality of position estimation systems include at leastone of a system using a Global Positioning System (GPS) receiver, asystem using an imaging device installed on the flight vehicle, a systemusing an imaging device for imaging the flight vehicle, a system using abarometer, and a system using an ultrasonic sensor.

(9)

The device according to (8),

wherein the system using the imaging device installed on the flightvehicle includes a system of estimating the position of the flightvehicle based on a known position at which a marker is arranged and acaptured image of the marker, which has been generated by the imagingdevice installed on the flight vehicle.

(10)

The device according to (8) or (9),

wherein the system using the imaging device installed on the flightvehicle includes simultaneous localization and mapping (SLAM) using amonocular imaging device that is installed on the flight vehicle byusing a gimbal such that an optical axis coincides with an axis in anup-down direction of the flight vehicle.

(11)

The device according to any one of (1) to (10),

wherein the first information includes information that indicatesacceleration of the flight vehicle, and

the second information is information that indicates the position of theflight vehicle.

(12)

The device according to any one of (1) to (11), further including:

a selection unit that dynamically selects a position estimation systemfrom among the plurality of position estimation systems during flight ofthe flight vehicle.

(13)

The device according to (12),

wherein the selection unit selects a first position estimation systemfrom among the plurality of position estimation systems,

the acquisition unit acquires information that indicates the firstposition estimation system,

the position estimation unit estimates the position of the flightvehicle from first information generated by using the inertial sensorand second information generated through the first position estimationsystem based on a parameter for the first position estimation system,

the selection unit selects a second position estimation system fromamong the plurality of position estimation systems after selecting thefirst position estimation system and provides the estimated position asan initial value of position estimation by the second positionestimation system,

the acquisition unit acquires information that indicates the secondposition estimation system, and

the position estimation unit estimates the position of the flightvehicle from the first information generated by using the inertialsensor and second information generated through the second positionestimation system based on a parameter for the second positionestimation system.

(14)

The device according to (13),

wherein the second position estimation system is a system for estimatinga relative position of the flight vehicle.

(15)

The device according to any one of (12) to (14),

wherein the selection unit newly selects a position estimation systemfrom among the plurality of position estimation system if the positionof the flight vehicle satisfies a predetermined positional condition.

(16)

The device according to any one of (12) to (15),

wherein the selection unit selects a position estimation system fromamong the plurality of position estimation systems based on reliabilitythat is dynamically calculated for each of the plurality of positionestimation systems.

(17)

The device according to any one of (1) to (16),

wherein the acquisition unit acquires information that indicates two ormore position estimation systems selected from among the plurality ofposition estimation systems, and

the position estimation unit estimates the position of the flightvehicle from the first information generated by using the inertialsensor and second information generated through each of the two or moreposition estimation systems based on a parameter for each of the two ormore position estimation systems.

(18)

The device according to any one of (1) to (17),

wherein the device is the flight vehicle or a module for the flightvehicle.

(19) A method including:

causing a processor to

-   -   acquire information that indicates a position estimation system        selected from among a plurality of position estimation systems        for estimating a position of a flight vehicle, and    -   estimate the position of the flight vehicle from first        information generated by using an inertial sensor of the flight        vehicle and second information generated through the position        estimation system based on a parameter for the position        estimation system.        (20)

A program that causes a processor to

acquire information that indicates a position estimation system selectedfrom among a plurality of position estimation systems for estimating aposition of a flight vehicle, and

estimate the position of the flight vehicle from first informationgenerated by using an inertial sensor of the flight vehicle and secondinformation generated through the position estimation system based on aparameter for the position estimation system.

REFERENCE SIGNS LIST

-   1 system-   51, 93 marker-   100 flight vehicle-   171 selection unit-   173 information acquisition unit-   179 position estimation unit-   200 control device-   300 piloting device-   400 information processing device-   410, 420 imaging device

The invention claimed is:
 1. A device, comprising: circuitry configuredto: acquire, from a first position estimation system of a plurality ofposition estimation systems, first information of a flight vehicle;acquire, from a first inertial sensor, linear motion information of theflight vehicle; acquire, from a second inertial sensor, angular motioninformation of the flight vehicle; execute a first function on thelinear motion information to generate second information of the flightvehicle; execute a second function on the angular motion information togenerate third information of the flight vehicle, wherein the secondfunction is complementary of the first function; and estimate a positionof the flight vehicle based on the first information, the secondinformation and the third information.
 2. The device according to claim1, wherein the first position estimation system is configured togenerate the first information, based on a parameter for the firstposition estimation system, and wherein the parameter corresponds to atime delay associated with the first position estimation system.
 3. Thedevice according to claim 2, wherein the circuitry is further configuredto: calculate a correction value from the first information based on thetime delay; and estimate the position of the flight vehicle from thecorrection value.
 4. The device according to claim 3, wherein thecircuitry is further configured to: acquire fourth information thatindicates a previously estimated position of the flight vehicle; andcalculate the correction value from the first information and the fourthinformation.
 5. The device according to claim 1, wherein the firstposition estimation system is configured to generate the firstinformation, based on a parameter for the first position estimationsystem, and wherein the parameter corresponds to a property of noiseassociated with the first position estimation system.
 6. The deviceaccording to claim 5, wherein the circuitry is further configured to:calculate a correction value from the first information based on theproperty of the noise; and estimate the position of the flight vehiclefrom the correction value.
 7. The device according to claim 6, whereinthe parameter corresponding to the property of noise is a time constantof a filter.
 8. The device according to claim 1, wherein the pluralityof position estimation systems include: a first system that includes aGlobal Positioning System (GPS) receiver; a second system that includesan imaging device installed on the flight vehicle; a third system thatincludes an imaging device for imaging the flight vehicle; a fourthsystem that includes a barometer; and a fifth system that includes anultrasonic sensor.
 9. The device according to claim 8, wherein theimaging device installed on the flight vehicle includes a system toestimate the position of the flight vehicle based on a known position atwhich a marker is installed in a specific area and a captured image ofthe marker generated by the imaging device installed on the flightvehicle.
 10. The device according to claim 8, wherein the imaging deviceinstalled on the flight vehicle includes simultaneous localization andmapping (SLAM) using a monocular imaging device installed on the flightvehicle by using a gimbal such that an optical axis of the monocularimaging device coincides with an axis in an up-down direction of theflight vehicle.
 11. The device according to claim 1, wherein the linearmotion information indicates acceleration of the flight vehicle, and theangular motion information indicates the position of the flight vehicle.12. The device according to claim 1, wherein the circuitry is furtherconfigured to dynamically select the first position estimation systemfrom among the plurality of position estimation systems during flight ofthe flight vehicle.
 13. The device according to claim 1, wherein thecircuitry is further configured to: select a second position estimationsystem from among the plurality of position estimation systems afterselection of the first position estimation system; transmit theestimated position as an initial value of position estimation to thesecond position estimation system; acquire, from the second positionestimation system, fourth information of the flight vehicle; andestimate a new position of the flight vehicle based on the fourthinformation, the second information and the third information.
 14. Thedevice according to claim 13, wherein the second position estimationsystem is a system for estimating a relative position of the flightvehicle.
 15. The device according to claim 12, wherein the circuitry isfurther configured to select a second position estimation system fromamong the plurality of position estimation systems if the estimatedposition of the flight vehicle satisfies a positional condition.
 16. Thedevice according to claim 12, wherein the circuitry is furtherconfigured to select a second position estimation system from among theplurality of position estimation systems based on reliability of each ofthe plurality of position estimation systems.
 17. The device accordingto claim 1, wherein the circuitry is further configured to: acquire fromat least two position estimation systems of the plurality of positionestimation systems, fourth information of the flight vehicle; andestimate the position of the flight vehicle based on the fourthinformation, the second information and the third information.
 18. Thedevice according to claim 1, wherein the device is one of the flightvehicle or a module for the flight vehicle.
 19. A method comprising: ina device: acquiring, from a position estimation system of a plurality ofposition estimation systems, first information of a flight vehicle;acquiring, from a first inertial sensor, linear motion information ofthe flight vehicle; acquiring, from a second inertial sensor, angularmotion information of the flight vehicle; executing a first function onthe linear motion information to generate second information of theflight vehicle; executing a second function on the angular motioninformation to generate third information of the flight vehicle, whereinthe second function is complementary of the first function; andestimating a position of the flight vehicle based on the firstinformation, the second information, and the third information.
 20. Anon-transitory computer-readable medium having stored thereoncomputer-readable instructions, which when executed by a computer, causethe computer to execute operations, the operations comprising: acquiringfrom a position estimation system of a plurality of position estimationsystems, first information of a flight vehicle; acquiring, from a firstinertial sensor, linear motion information of the flight vehicle;acquiring, from a second inertial sensor, angular motion information ofthe flight vehicle; executing a first function on the linear motioninformation to generate second information of the flight vehicle;executing a second function on the angular motion information togenerate third information of the flight vehicle, wherein the secondfunction is complementary of the first function; and estimating aposition of the flight vehicle based on the first information, thesecond information, and the third information.